Gas turbine apparatus



Sept. 7, 1948. 5. WAY

GAS TURBINE APPARATUS.

Filed lay 1, 1946 INVENTIOR STEWART WAY ATTORNEY Rim Patented Sept. 7, 1948 GAS TURBINE APPARATUS Stewart Way, Churchill Borough, 2a., assignmto Westinghouse Electric corpora on. East Pittslvanla burgh, Pa., a corporation of Penny Application May 1, 1946, Serial No. 666,374

This invention relates to power plants and particularly to combustion apparatus for a gas turblue and it has for an object to provide an improved device of the character set forth.

The present invention, although not limited thereto, is particularly adapted for use in a gas turbine power plant of the type employed on air- 3 Claims. (cites-19) craft to drive the propeller or electric generator or to supply motive fluid for jet propulsion of the aircraft. Such a plant preferably comprises a streamlined tubular casin haying mounted axially therein a compressor adjacent the forward or inlet end, .a turbine adjacent the rearward or discharge end, and combustion apparatus located between the compressor and turbine for heating the compressed air and which discharges the hot gases at a suitable temperature and pressure to the turbine. The spent gases on leaving the turbine are discharged through a nozzle provided at the rear of the casing and may aid in propelling the aircraft It is imperative that the physical dimensions and weight of a plant of this character be kept at an absolute minimum, and consequently the combustion apparatus must be small requiring it annular members welded to the adjacent steps and one of the steps is slotted between the weld connections to provide for free relative expansion and contraction of the stepped structure upon changes in temperature.

Yet another object of the invention is to provide a combustion chamber wall construction wherein a corrugated separator is arranged Between portions cf smaller and larger diameters of adjacent sections of the wall. the separator being connected to the portion of smaller diameter and being welded to tongues on the portion of larger diameter, the tongues being provided by slits or slots between the welded connections.

A further object of the invention is to rovide a combustion chamber wall of stepped formation in which the risers are comprised by strips overlapping the step below and overlapped by the step above, the two overlaps being in oflset or nonoverlying relation to each other, whereby the overlapped portions of the risers and associated tofunction with high velocities of flow and realize rates of energy release or the order of" x 10 B. t. u. per cubic foot per hour.

If the power plant is mounted in a nacelle or built into a wing, and even when mounted in the fuselage, the frontal area of the plant must be maintained at a minimum to reduce drag through the plant, with the result that the velocities of the hot gases leaving. the combustion apparatus are high and these velocities should be about 200 to 300 feet per second.

It is accordingly a further object to provide a combustion apparatus of small size which is capable of handling a large volume of air and fuel mixture and complete combustion or the fuel in a relatively small space.

A power plant of this character operates over a wide range of fuel rates since the fuel rate for peak load, as at take-oil, may be as much as ten times that for idling at high elevation. Further, the combustion apparatus must be able to burn the fuel and heat the air supplied by the compressor toa peak temperature which may be 1500 F. or even higher without danger of distorting'the walls or causing" excessive creep or corrosion of the apparatus.

Therefore, another object of this invention is to provide combustion apparatus including an annular wall of stepped formation in which the risers are comprised by corrugated or convoluted invention as will be apparent from the following steps may be easily secured as by welding, riveting, etc,

The pressure drop across the combustion chamber, comparing the state of two stations of equal velocity, should be kept at an absolute minimum since the pressuredrop decreases the power which can be developed by the turbine driven by the hot gases discharging from the combustion apparatus.

The above-mentioned features, limitations, and requirements for the combustion apparatus of the gas turbine power plant for aircraft use apply also, but perhaps not as critically, to gas turbine power plants on small vessels of high power and speed, particularly naval craft or in any installation where space and weight are at a premium.

It is, accordingly, a further object of the invention to provide an improved combustion apparatus capable of satisfying the above-mentioned limitations and requirements in a gas turbine power plant.

, These and other objects are efiected by the description and claims taken in connection with the accompanying drawings, forming a part of this a plication, in which:

Fig. 1 is a side elevational view of a gas turbine power plant embodying the present invention, a

portion or the outer casing and of the burner tubes being broken away to better illustrate the combustion apparatus, the novel subject matter of the application;

Fig. 2 is a sectional view taken along the line 11-11 of Fig.- 1. looking in the direction indicated by the arrows;

Fig. 3 is an enlarged sectional view of the combustion apparatus illustrated in Fig. 1;

Fig. 4 is a transverse sectional view taken along the line IV-IV of Fig. 3, looking in the direction indicated by the arrows; and v Fig. is a developed plan of the structure shown in Fig. 4.

The power plant shown in Fig. 1 and generally indicated III, is adapted to be mounted in or on the fuselage or wing of an airplane with the left or intake end ii, as viewed in this figure, pointed in the direction of flight.

The plant comprises an outer shell or casing structure I2 providing an annular air duct or passage l3 extending fore and aft with respect to the aircraft. This casing has mounted therein along its longitudinal axis a fairing cone l4 adapted to house gearing connected through a hollow guide vane IS with auxiliaries IS, an axial-- flow compressor ll, combustion apparatus generally indicated i8, a turbine I8 which drives the compressor, and a nozzle 2| defined by the casing l2 and by a tailpiece 22,,the latter being mounted concentrically in the casing and cooperating with the latter to provide a propulsion jet.

Air enters at the intake end II and flows substantially straight through the plant, i passing through the compressor ll, where it is compressed, and into the combustion apparatus It, where it is heated. The hot gases, comprising the products of combustion and excess air heated by the combustion, on leaving the combustion apparatus, are directed by suitable guide vanes or nozzles 23 against the blades 24 of the turbine disc 25 and then are discharged through the propulsion nozzle 2! to propel the aircraft.

The present invention is not limited to the specific details or arrangement of the structure thus far described, but it is primarily concerned with the combustion apparatus which heats the compressed air supplied by the compressor without disturbing the straight-through flow of the plant, thereby permitting a design of small maximum diameter.

and the outer casing structure of small maximum diameter, the combustion apparatus is divided by wall structure into an air space or spaces 3| open to the discharge end of av diffuser passage 32 leading from the compressor, and which overlap a burner space or spaces 83 open to a passage 34 leading to the turbine guide vanes 23. Atomized fuel is supplied to the forward end of the burner space or spaces which are also provided with ignition means. The dividing :wall structure has openings therein to provide for entry into the burner space of compressed air from the overlapping air spaces, the

entering air supporting combustion of fuel and mixing with the hot products of combustion to provide a motive fluid comprising a mixture of air and products of combustion of suitable temperature for driving the turbine.

The dividing wall structure separating the air and burner spaces may be constituted in any suitable manner, provided that it is disposed so 45 tions of greater diameter.

60 ing or riveting.

that the air space overlaps axially the burner space or spaces and so that air may flow into the latter along the structure to enable combustion to be completed or substantially com- 5 pleted within the axial length or the burner spaces. In this way, the axial length of the apparatus is kept at a minimum because it does not require the division of the air stream into two distinct streams of primary and secondary air, the primary air being used to complete the combustion, with the remaining secondary air stream being mixed with the combusted gases to lower the final temperature.

Referring now to the details of construction illustrated in Figs. 3 to 5, inclusive, there is shown a combustion chamber 4|. defined by inner and outer annular walls 4| and 42, respectively. and extending downstream from the nozzle manifold 48 which carries a plurality of nozzles 44 adapted to admit fuel to the upstream the inner-wall is of progressively decreasing diameter from the upstream to the downstream end thereof while the outer wall is of progressively increasing diameter in the same direction, rthis arrangement providing a combustion chamber 40 of progressively increasing crosssectional area from its upstream end to its downstream end. Therefore, it is believed necessary to describe in detail only the outer wall 42, which comprises a series of annular sections 35 41, 48 and 4| joined at their adjacent terminal portions by spacer members Ii which overlapthe adjacent sections of smaller diameter and are overlapped by adiacent-sections of larger diameter.

The spacer members II are in the form of circumferentially corrugated rings whose inwardlydepressed portions ll contact the adjacent sections of smaller diameter and whose outwardlyprojecting portions a contact the adjacent sec- The spacer members are permanently secured to the adjacent terminal portions of the annular sections by suitable means, preferably by spot-welding, at a plurality of the points of contact.

As will be apparent upon reference to Fig. 3,

the joined ends of adjacent sections, such as 41- and 48-. do not overlap but are substantially radially aligned. If adjacent sections were overlapped a distance corresponding to the 3 axial extent of the spacer members Bl, these spacers would be covered both on the inside and the outside. with the result that it would be exceedingly difficult, if not impossible, to secure them to the associated annular sectionsby weld. By limiting the overlapping of each annular section to approximately fifty per cent of the axial extent of the spacer it overlaps, welding or riveting of each connection is greatly facilitated.

as In order to prevent warpage of the wall structure or breakage of the connections between the spacing members and their associated annular sections, which might result if no suitable means were provided for avoiding such distortion, one

7 of the annular members is provided with axiallyextending slits or slots II between the weld connections or other connections l4. Preferably, the slits or slots are provided in the annular members which are downstream of the associated 7g spacer members II as these sections may be as much as aw r. cooler than the sections immediately upstream of the corresponding spacer members, and with temperature diiierenoes of this amount, means must be provided for cir cumferen'tial expansion.

While the invention has been shown in but one form, it will be obvious to those skilled in the-art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof.

What is claimed is:

1. In a combustion chamber adapted for admission of fuel to the upstream end thereof and discharge of hot gases from the downstream end thereof, an annularwall comprising a plurality of annular sections of diiferent sizes arranged concentrically and in order of increasing size from the upstream end toward the downstream end of said chamber with adjacent ends of the sections approximately aligned radially and with adjacent terminal portions of the sections radially spaced, and spacer members disposed in the radial spaces between adjacent terminal portions in overlapping relation to the latter.

2. In a combustion chamber, an outer annular wall of stepped construction, each of said steps comprising an annular section of materially greater diameter than the preceding section from the upstream to the downstream end of the chamber, and each riser of said stepped construction comprising a circumferentially-corrugated annular member overlapping the adja cent terminal portion of the adjacent section of smaller diameter and being overlapped by the adjacent terminal portion of the adjacent section rality of the outwardly-raised portions of the 6 corrugated risers and the terminal portions overlapping said risers, said overlapping terminal portions being slit axially intermediate said lastmentioned connections.

3. In a combustion chamber, an outer annular wall of stepped construction, each of said steps comprising an annular section of materially greater diameter than the preceding section from the upstream to the downstream end of the chamber, and each riser of said stepped construction comprising circumferentlally-corrugated annular members overlapping the adjacent terminal portion of the adjacent section of smaller diameter and being overlapped by the adjacent terminal portion of the adjacent section of larger diameter, weld connections between a plurality of the inwardly-depressed portions of the corrugated risers and the terminal portions overlapped thereby, and weld connections between a plurality of the outwardly-raised portions of the corrugated risers and the terminal portions overlapping said risers, said overlapping STEWART WAY.

REFERENCES CITED The following references are of record in the me or this patent:

UNITED STATES PATENTS Number Name a Date 1,311,335 Kemp July 29, 1919 2,288,464 Beippei Dec. 30, 1941 FOREIGN PATENTS Number Country Date 539,069 England Aug. 2'1, 1941 

